Cosine Quotes

For common purposes we may without sensible error suppose the earth's motion equable and neglect the corrections, and then the rule for the parallax of right ascension will be this: Sine lat. : rad. : : cotang. A : cotang. C, or rad : sine lat. : : tang. A : tang. C; then long. star \mp C = long. of λ. Cosine C : cosine A : : semi transverse axis : z. And cosine decl. cosine (ʘ - λ) :: z : x = parallax of right ascension. (James Bradley)